Warm air furnaces



Aug. 7, 1956 D. c. PATTEN WARM AIR FURNACES 3 Sheets-Sheet 1 Filed Oct. 30, 1952 afw/vza Aug. 7, 1956 D. c. PATTEN WARM AIR FURNACES 3 Sheets-Sheet 2 Filed 001;. so, 1952- 3 20% CPai/w 7, 1956 D. 'c. PATTEN 2,757,661

WARM AIR FURNACES Filed Oct. 50, 1952 I5 Sheets-Sheet 3 I 692 .34 r I 51 23 iii .u:

HOT AIR KPLEKUM Z3 I COLD AIR PLENUM cow AIR PLENUM fi United States Patent WARM AIR FURNACES Don C. Patten, Sycamore, 111., assignor to J. V. Patten Company, Sycamore, 111., a corporation of Illinois Application Dctoher 30, 1952, Serial No. 317 ,630

4 Claims. (Cl. 126-103) This invention relates generally to warm air furnaces and more particularly to an improved construction for providing good heat exchange between the combustion gases and the air to be warmed thereby.

The invention is characterized by chutes or ducts forming passageways for air to be warmed. The chutes are arranged substantially in the form of an inverted V and are joined along a line weld on their proximate faces, and extend through an opening in the top of a chamber for combustion gases to connect with either a cold air or hot air plenum. The hot gases within the combustion chamber impinge against the underside and proximate faces of the chutes to provide good heat exchange with air moving therethrough. A baffle plate joins the chutes along one side thereof, so that the gases are required to move through to the opposite sides of the chutes whence they are reversed in direction to pass over the remote and upper faces of the chutes and around the opposite side of the baffle before leaving the combustion chamber.

By such a construction extremely good heat exchange is had, and it is possible to construct a furnace embodying the above features having good heat exchange properties with only the simplest assemblies, which assemblies con sist principally of welded sheet or plate-like members, as contrasted with constructions requiring curved or cast members.

With the foregoing considerations in mind it is a principal object of this invention to provide a new and improved construction for warm air furnaces, which construction is characterized by affording extremely good heat exchange with a minimum of complicated and expensive parts.

Other and important objects of the invention will be: come apparent from a study of the following description taken with the drawings which together show a preferred embodiment of the invention and what is now considered to be the best mode of practicing the principles thereof. Other embodiments may be suggested to those having the benefits of the teachings herein, and it is therefore intended that the scope of the invention not be limited by the precise embodiment herein shown nor otherwise than by the scope and terms of the subjoined claims.

In the drawings:

Fig. 1 is a vertical sectioned view through a furnace having embodied therein the improvements according to the present invention;

Fig. 2 is a vertical section through the furnace shown in Fig. 1, along the line 22 and looking in the direction of the arrows;

Fig. 3 is a horizontal section taken along the line 3-3 of Fig. 2 looking in the direction of the arrows;

Fig. 4 is a perspective view of a baffle forming the assembly shown in Figs. 1 to 3 inclusive;

Fig. 5 is a perspective view of one of the chutes and the part of bafile shown in Figs. 1 to 4 inclusive, and showing the 2,757,661 Patented Aug. 7, 1956 and includes a closed walled chamber 11 for the combustion of fuel. By way of example, such fuel may be gas supplied by a pipe 12 to a burner 13. The precise form of such burner, or the kind of fuel forms no part of the present invention, but for the purpose of simplicity in describing the invention, such a furnace is particularly adapted for use with oil or gas fuels.

The closed chamber 11 is essentially rectangular in horizontal cross section and is composed of a rear wall 16, a front wall 18, and opposite side walls 17 and 19. The chamber 11 is closed by a bottom plate 21 welded to the bottom edges of the aforesaid walls and a top plate 22 welded to the top edges thereof.

The chamber 11 is surrounded by a jacket 14 having its Walls 23, 24, 26 and 27 spaced from the walls 16, 17,

18 and 19 so as to provide circulation of air past the same. The jacket 14 rests upon a floor 28, and the walls thereof are held at their bottom edges to angle members 29 which may be bolted or otherwise held to the floor 28.

The chamber 11 is held in position in spaced relationship to the jacket 14 and above the floor 28 by mounting legs 31 which are welded at 32 to the Walls of the chamber 11 and secured by rivets 30 to the angle members 29.

An access pouch assembly and inspection door for the burner 13 is held in an opening 33 at the lower end of the wall 16 of the chamber 11. The assembly includes a frame 34 flanking the opening 33 and having a flange 36 extending therefrom. The flange 36 and the frame 34 extend across the space between the wall 16 and the jacket wall 23, and the edges of the flange are welded to the opening 33 by welds 37 as seen more particularly in Fig. 1.

A furnace door 39 covers an opening 41 in the Wall 23 and is held by cap bolts 40 to the outer jacket 14. The opening 41 is in register with the opening 33. Louvered openings 42 are provided in the door 39 near the lower end thereof for the passage of air insuring good combustion of the fuel at the burner 13. As seen in Fig. 1, the door 39 has an inspection port 43 which is closed by a cover 44- secured to the door 39 in any convenient manner, and readily detachable therefrom.

A plenum indicated generally by the reference numeral 45 is disposed on top of the jacket 14. As seen in Figs. 1 and 2, the tops of the Walls of the jacket are bent inward as at 46 and then bent upward as at 47 to provide a seat for the plenum 45 and a flange for locating the walls of said plenum.

In the form shown in Figs. 1 and 2, the plenum 45 is for cold air arranged to be blown downward for heat exchange with the products of combustion of the burner 13. Such a plenum is provided with a blower, not shown, arranged to move the cold air downward in such heat exchange relationship, so that the warmed air may leave the furnace by way of a hot air plenum 48 disposed in the floor 28 supporting the furnace 10.

Such a form of the invention may be indicated for crawl-space installations, such as are found in structures lacking basement or cellar areas. Such an installation is indicated schematically in Fig. 7 of the drawings. Alter-.

cases is disposed on top of the furnace 10.

Means are provided for circulating air between the plenum 45 and the space afforded between the outer jacket 14 and the closed chamber 11, in such a fashion as to provide good heat exchange with the products of combustion of the burner 13. To this end opposed side walls 17 and 19 of the closed chamber 11 are provided respectively with rectangular openings 51 and 52 for chutes or ducts 53 and 54. Each of the chutes is rectangular in cross section and extends inward from the space between the chamber 11 and the outer jacket to converge with the opposite chute in an upward direction as seen more particularly in Fig. 2. The top of the chutes 53 and 54 extend through a rectangular opening 56 in the top plate 22 of the closed chamber 11, and are held to each other by a gas tight weld 57 and to the top plate by a weld 58. Each chute 53 and 54 is likewise held to the sidewalls 17 and 19 respectively by gas tight welds 59.

The dimension in cross section of each chute 53 and 54 is so chosen that front sides 61 and 62 respectively thereof are spaced from the front wall 18 of the closed chamber 11, as seen more clearly in Fig. 3. Similarly, rear sides 63 and 64 respectively thereof are spaced from the rear wall 16 of the closed chamber 11.

The rear sides 63 and 64 are welded to a baflle plate 66 of a generally trapezoidal shape as seen in Fig. 4. An upper edge 67 of the baffle plate 66 bears against the underside of the top plate 22 of the chamber 11. A bathe plate 68 extends horizontally below the vertical baflle plate 66 and bridges the distance between sides 63 and 64 of the chutes 53 and 54 and the rear wall 16 of chamber 11. The baflle plate 68 has an upturned flange 69 which abuts a lower edge 71 of the vertical batfle plate 66 and an upturned flange 72 which is welded to the rear wall 16 so as to hold the battle plate 68 in position. The batfle plate 68 extends for the distance between the sidewalls 17 and 19 of the closed chamber 11.

For installations employing gas as a fuel, as with the embodiment of Figs. 1 to 3, a baffle plate 73 is mounted above the burner 13. Angles 74 spaced inward from the side walls 17 and 19 are held at their ends to the other walls 16 and 18 by welds 76. Clips 77 extending from the bafile plate 73 are bent around the vertical legs of the angles 74, as seen in Fig. 2. Spacers 78 extend from the bathe 73 to bear against the rear wall 16 and front wall 18. It will be seen that the combustion gases are thus diverted around the sides and ends of the bafile 73 thereby to slow up the movement of same, so that a greater degree of heat exchange is accomplished.

The combustion gases thence move upward to impinge against the sloping and converging proximate faces of the ducts or chutes 53 and 54. The vertical baffle plate 66 and the horizontal batfle plate 68 prevent a direct path of movement of the combustion gases to a flue pipe 79 located transversely of the chutes 53 and 54 and extending through an opening 81 in the outer jacket 14, and having a flange 82 which is welded to the interior face of the wall 16 of the chamber 11. A stack fitting 83 is connected to the flue pipe 82 and in turn to a stack pipe 84.

The combustion gases are thus diverted by the vertical battle plate 66 and the horizontal baflle plate 68 so that the gases must first move over the proximate faces of the inclined chutes or ducts 53 and 54 and then over the front sides 61 and 62 of the chutes 53 and 54 within the chamber 11, to be then reversed in direction to move over the remote faces of the ducts 53 and 54. After so moving over the remote faces in the manner described the gases move to the space defined by the vertical battle plate 66, the horizontal battle plate 68 and the rear wall 16 of chamber 11 to escape by the vent pipe 79.

In installations employing gas as a fuel the flue pipe may be partially battled by a vent pipe restrictor 86, for additionally retarding the movement of the combustion gases.

The furnace is provided with a cleanout opening 87 fitted with a closure 88 mounted on the outer jacket, so

4 that the surfaces in heat exchange relationship may readily be cleaned.

In the form of the invention shown in Figs. 1 to 3, the cool air within plenum chamber 45 is forced by the blower, not shown, downward through the chutes or ducts 53 and 54, where it is warmed by heat exchange with the combustion gases, the so warmed air being discharged at the lower end of such chutes into the space between the outer jacket 14 and the chamber 11, whence it moves into the warm air plenum 48 in the floor 28. In Fig. 7, such an arrangement is shown schematically, while in Fig. 6 there is shown an arrangement wherein the cold air plenum 45 is disposed beneath the furnace 10 with the warm air plenum atop thereof.

Irrespective of the direction of air flow through the chutes or ducts 53 and 54, extremely good heat exchange is had between the combustion gases and the air to be warmed. The convergence of the ducts within the chamber 11 together with vertical battle 66 and the horizontal bafile 68 provides a path of movement of the combustion gases whereby the maximum amount of heat is extracted from the gases before escaping via the flue 79. In tests of structures as disclosed herein overall thermal efliciency of eighty-three percent has been attained, which is extremely high.

In the embodiment of the invention described herein substantially all of the parts contributing to heat transfer are fabricated from flat sheets or plates. Fabrication from such material, and the employment of welding procedures in such fabrication provide an efficient furnace at a lower cost than possible heretofore.

The inclined chutes or ducts and the combustion chamber have all been shown of a rectangular configuration. It is entirely within the scope of the invention, however. that the chutes or ducts be constructed of tubes disposed in juxtaposed relationship and converging toward each other, or cylindrical or elliptical tubes also converging toward each other and having battles at one side thereof to divert and cause movement of the gases in the manner described. Likewise the combustion chamber may be cylindrical in shape, employing therewith ducts or chutes of the form described herein or of the form as just adverted to.

While the invention has been described in terms of a preferred embodiment thereof, its scope is not intended to be limited by the precise embodiment herein shown not otherwise than by the terms of the claims here appended.

I claim:

I. In a warm air furnace, walls forming a chamber of rectangular cross section defining a space for combustion of fuel, a flue opening in the rear wall of said chamber, ducts extending substantially parallel to the plane of said flue opening and said rear wall providing for circulation of air in heat exchange relationship with the gaseous products of fuel combustion, said ducts extending through opposed side walls of said chamber and in directions inwardly and upwardly toward each other and extending at least to an opening in a top wall of said chamber, said ducts being joined along a line on their proximate surfaces, said line of joining being substantially in the plane of said top wall so as to provide below said joining line an area for impingement by said gaseous products on the lower sides of said ducts, a vertical baffie secured to the rear sides of said ducts and interposed between said ducts and said fiue opening. said vertical batfle extending upward to said top wall to prevent any direct passage of combustion gases past said battle, and a battle plate contacting the lower edge of said vertical baffle and extending in a substantially horizontal plane from said vertical bafile and between the rear sides of said ducts and said rear wall along a line below said flue opening, said battle plate extending also for the distance between said side walls, said baflle and said battle plate together with the convergence of said ducts providing for travel in one direction of all of the products of combustion over the proximate faces of said ducts and in the opposite direction over the remote faces of said ducts before leaving said chamber at the flue opening thereof, the front sides of said ducts being spaced from the front wall of said chamber to provide a passageway for the movement of all of said gases before moving over the said remote faces.

2. In a warm air furnace, walls forming a chamber of rectangular cross section defining a'space for combustion of fuel, a flue opening in the rear wall of said chamber, ducts extending substantially parallel to the plane of said flue opening and said rear wall and having their sides spaced from the front and rear walls of said chamber and providing for circulation of air in heat exchange relationship with the products of fuel combustion, said ducts extending through the side Walls of said chamber and in directions inwardly and upwardly toward each other and extending at least to an opening in a top wall of said chamber, said ducts being joined along a line on their proximate surfaces, said line of joining being substantially in the plane of said top wall so as to provide an area below said joining line for impingement by the products of fuel combustion on the lower side of said ducts, a vertical baflie secured to the sides of said ducts and interposed between said ducts and said flue opening, said vertical baffle extending upward to said joining line to prevent any direct passage of combustion gases past said bafiie, and a baffle plate extending in a substantially horizontal plane from said vertical baffle adjacent the lower edge of the latter and between the sides of said ducts and said rear wall along a line below said flue opening, said baflie plate extending also for the distance between said side walls, said baflie and said baflie plate together with the convergence of said ducts providing for travel in one direction of all of the products of fuel combustion over the proximate faces of said ducts and in the opposite direction over the remote facesof said ducts before leaving said chamber at the flue opening thereof.

3. In a warm air furnace, walls forming a chamber of substantially rectangular cross section defining a space for combustion of fuel, a flue opening in an end wall of said chamber, a substantially rectangular opening formed in each of the side walls of said chamber, a single rec tangular opening formed in the top wall of said chamber, a rectangular duct passing through each of the substantially rectangular openings in said side walls, said ducts extending upwardly and inwardly in convergent directions toward each other and being joined along a single line on their proximate faces substantially in the plane of said top opening, said ducts being welded at their lower ends to the said openings in said side Walls and at their upper ends at said top opening, the dimensions of said convergent ducts being such as to be spaced but slightly from the end walls of said chamber, the joining of said ducts providing an area below such joining line for the impingement of combustion gases, a vertical baffle secured to corresponding side walls of said ducts and interposed between said ducts and said flue opening, said vertical baffle extending upward to said joining line to prevent any direct passage of combustion gases past said bafile, and a baffle plate adjacent the lower edge of said vertical baffle extending in a substantially horizontal plane below said flue opening from said vertical balfle and between said corresponding sides of said ducts and said end wall having said flue opening, said baflle plate extending also for the distance between said side walls, said vertical baffle and said baflle plate together with the convergence of said ducts providing for travel in one direction of all of the products of combustion over the proximate faces of said ducts and in the opposite direction over the remote faces of said ducts before leaving said chamber at the flue opening thereof.

4. A warm air furnace comprising walls forming a chamber of rectangular cross section defining a space for combustion of fuel, a jacket surrounding said chamber and spaced therefrom, a plenum chamber disposed above said chamber, a flue opening in the rear wall of said chamber, ducts spaced from the front and rear walls of said chamber and extending substantially parallel to the plane of said flue opening in the said rear wall and providing for circulation of air between the spaces defined by said jacket and said plenum in heat exchange relationship with gaseous products of fuel combustion, said ducts extending inwardly through opposed side walls of said chamber in convergent directions and upwardly to an opening in a top wall in said walled chamber to communicate with said plenum, said ducts being joined along a line on their proximate surfaces near the top wall of said chamber to provide an area below such join ing line for impingement by said gases, a vertical baffle secured to one of the sides of said convergent ducts and interposed between said sides of said convergent ducts and said flue opening, said vertical baflie extending upward to said joining line to prevent any direct passage of combustion gases past said vertical baflie, and a baflie plate extending in a plane below said flue opening from said vertical baffle adjacent the lower edge of said vertical baffle in a substantially horizontal plane between the aforesaid sides of said ducts and the said wall having the flue opening therein, said baffle plate extending also for the distance between the aforesaid opposed side walls of said chamber, said vertical baflle and said horizontal baflle plate together with the convergence of said ducts providing for travel in one direction of the prod nets of combustion over the proximate faces of said ducts and in the opposite direction over the remote faces of said ducts before leaving said chamber at the flue opening thereof, the opposite sides of said ducts being spaced from the opposite walls of said chamber to provide a passageway for the movement of said gases before moving over said remote faces.

7 References Cited in the file of this patent UNITED STATES PATENTS 538,701 Robinson May 7, 1895 1,259,985 Holmes et a1. Mar. 19, 1918 1,526,891 Anderson Feb. 17, 1925 2,109,876 Bard Mar. 1, 1938 

